3,488 research outputs found
Разработка и применение интеллектуальных технологий и оборудования для обработки семян
Seed processing is an important link in the seed industry chain. Crop seed industry is a national strategic and basic core of industry. Drying, cleaning, selecting, grading, coating, packaging and storage of crop seeds are the main measures to realize the precision sowing of crops and the increase of grain yield and income. Continuously improving the intelligence and fi ne level of seed processing equipment is of great signifi cance to ensure the production and supply of excellent seeds and the stability of agricultural production. This paper describes the development status of modern seed processing equipment technology in China, introduces the establishment of seed processing equipment engineering technology research center, taking maize, rice, wheat and cotton seed processing technology and machinery as an example, describes the key technologies and technological process of the breakthrough in the major crop seed processing, analyzes the existing problems of seed processing equipment in China at this stage as well as the development trend in the future, provides a reference for government decision makers in resolving the problem of mechanical damage in the process of seed processing and further improving the intellectualization level of seed processing, promotes the common progress of the global seed processing equipment technology.Обработка семян – важное звено в цепочке семеноводства. Отрасль растениеводства – это национальная стратегическая и базовая отрасль промышленности страны. Сушка, очистка, отбор, сортировка, дражирование, упаковка и хранение семян сельскохозяйственных культур являются основными мерами по обеспечению точного посева сельскохозяйственных культур и увеличения урожайности и доходов зерна. Постоянное повышение интеллектуального уровня оборудования для обработки семян имеет большое значение для получения и поставки отличных семян и обеспечения стабильности сельскохозяйственного производства. В этой работе описывается состояние разработки современного оборудования для обработки семян в Китае, рассказывается о создании центра инженерных технологий оборудования для обработки семян. На примере технологий и оборудования для обработки семян кукурузы, риса, пшеницы и хлопка описываются ключевые технологии и технологический процесс, лежащие в основе технологического прорыва в обработке семян основных сельскохозяйственных культур. Анализируются существующие проблемы, связанные с оборудованием для обработки семян в Китае на данном этапе, а также будущие тенденции развития обработки семян. Статья предоставляет рекомендации для лиц, принимающих правительственные решения в области проблем механических повреждений семян в процессе обработки и решения о дальнейшем повышении уровня интеллектуализации обработки семенного материала. Данная работа способствует дальнейшему развитию глобальных технологий в этой сфере
Conformal transformation in theories
It is well-known that theories are dynamically equivalent to a
particular class of scalar-tensor theories. In analogy to the extension
of the Einstein-Hilbert action of general relativity, theories are
generalizations of the action of teleparallel gravity. The field equations are
always second order, remarkably simpler than theories. It is interesting
to investigate whether theories have the similar conformal features
possessed in theories. It is shown, however, that theories are
not dynamically equivalent to teleparallel action plus a scalar field via
conformal transformation, there appears an additional scalar-torsion coupling
term. We discuss briefly what constraint of this coupling term may be put on
theories from observations of the solar system.Comment: 4 pages, Revision to be publishe
Dirac Equation with Spin Symmetry for the Modified P\"oschl-Teller Potential in -dimensions
We present solutions of the Dirac equation with spin symmetry for vector and
scalar modified P\"oschl-Teller potential within framework of an approximation
of the centrifugal term. The relativistic energy spectrum is obtained using the
Nikiforov-Uvarov method and the two-component spinor wavefunctions are obtain
are in terms of the Jacobi polynomials. It is found that there exist only
positive-energy states for bound states under spin symmetry, and the energy
levels increase with the dimension and the potential range parameter .Comment: 9 pages and 1tabl
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A New Remote Guided Method for Supervised Web-Based Cognitive Testing to Ensure High Quality Data
Background. The global COVID-19 pandemic has triggered a fundamental reexamination of how human psychological research can be conducted both safely and robustly in a new era of digital working and physical distancing. Online web-based testing has risen to the fore as a promising solution for rapid mass collection of cognitive data without requiring human contact. However, a long-standing debate exists over the data quality and validity of web-based studies. Here, we examine the opportunities and challenges afforded by the societal shift toward web-based testing, highlight an urgent need to establish a standard data quality assurance framework for online studies, and develop and validate a new supervised online testing methodology, remote guided testing (RGT).
Methods. A total of 85 healthy young adults were tested on 10 cognitive tasks assessing executive functioning (flexibility, memory and inhibition) and learning. Tasks were administered either face-to-face in the laboratory (N=41) or online using remote guided testing (N=44), delivered using identical web-based platforms (CANTAB, Inquisit and i-ABC). Data quality was assessed using detailed trial-level measures (missed trials, outlying and excluded responses, response times), as well as overall task performance measures.
Results. The results indicated that, across all measures of data quality and performance, RGT data was statistically-equivalent to data collected in person in the lab. Moreover, RGT participants out-performed the lab group on measured verbal intelligence, which could reflect test environment differences, including possible effects of mask-wearing on communication.
Conclusions. These data suggest that the RGT methodology could help to ameliorate concerns regarding online data quality and - particularly for studies involving high-risk or rare cohorts - offer an alternative for collecting high-quality human cognitive data without requiring in-person physical attendance.Biotechnology and Biological Sciences Research Council (H012508 and BB/P021255/1).
Wellcome Trust (205067/Z/16/Z)
Global Ethics and Nanotechnology: A Comparison of the Nanoethics Environments of the EU and China
The following article offers a brief overview of current nanotechnology policy, regulation and ethics in Europe and The People’s Republic of China with the intent of noting (dis)similarities in approach, before focusing on the involvement of the public in science and technology policy (i.e. participatory Technology Assessment). The conclusions of this article are, that (a) in terms of nanosafety as expressed through policy and regulation, China PR and the EU have similar approaches towards, and concerns about, nanotoxicity—the official debate on benefits and risks is not markedly different in the two regions; (b) that there is a similar economic drive behind both regions’ approach to nanodevelopment, the difference being the degree of public concern admitted; and (c) participation in decision-making is fundamentally different in the two regions. Thus in China PR, the focus is on the responsibility of the scientist; in the EU, it is about government accountability to the public. The formulation of a Code of Conduct for scientists in both regions (China PR’s predicted for 2012) reveals both similarity and difference in approach to nanotechnology development. This may change, since individual responsibility alone cannot guide S&T development, and as public participation is increasingly seen globally as integral to governmental decision-making
A review of physical supply and EROI of fossil fuels in China
This paper reviews China’s future fossil fuel supply from the perspectives of physical output and net energy output. Comprehensive analyses of physical output of fossil fuels suggest that China’s total oil production will likely reach its peak, at about 230 Mt/year (or 9.6 EJ/year), in 2018; its total gas production will peak at around 350 Bcm/year (or 13.6 EJ/year) in 2040, while coal production will peak at about 4400 Mt/year (or 91.9 EJ/year) around 2020 or so. In terms of the forecast production of these fuels, there are significant differences among current studies. These differences can be mainly explained by different ultimately recoverable resources assumptions, the nature of the models used, and differences in the historical production data. Due to the future constraints on fossil fuels production, a large gap is projected to grow between domestic supply and demand, which will need to be met by increasing imports. Net energy analyses show that both coal and oil and gas production show a steady declining trend of EROI (energy return on investment) due to the depletion of shallow-buried coal resources and conventional oil and gas resources, which is generally consistent with the approaching peaks of physical production of fossil fuels. The peaks of fossil fuels production, coupled with the decline in EROI ratios, are likely to challenge the sustainable development of Chinese society unless new abundant energy resources with high EROI values can be found
Rigidly Supersymmetric Gauge Theories on Curved Superspace
In this note we construct rigidly supersymmetric gauged sigma models and
gauge theories on certain Einstein four-manifolds, and discuss constraints on
these theories. In work elsewhere, it was recently shown that on some
nontrivial Einstein four-manifolds such as AdS, N=1 rigidly supersymmetric
sigma models are constrained to have target spaces with exact K\"ahler forms.
Similarly, in gauged sigma models and gauge theories, we find that
supersymmetry imposes constraints on Fayet-Iliopoulos parameters, which have
the effect of enforcing that K\"ahler forms on quotient spaces be exact. We
also discuss general aspects of universality classes of gauged sigma models, as
encoded by stacks, and also discuss affine bundle structures implicit in these
constructions.Comment: 23 pages; references added; more discussion added; v4: typos fixe
Intracellular Calcium Disturbances Induced by Arsenic and Its Methylated Derivatives in Relation to Genomic Damage and Apoptosis Induction
Arsenic and its methylated derivatives are contaminants of air, water, and food and are known as toxicants and carcinogens. Arsenic compounds are also being used as cancer chemotherapeutic agents. In humans, inorganic arsenic is metabolically methylated to mono-, di-, and trimethylated forms. Recent findings suggest that the methylation reactions represent a toxification rather than a detoxification pathway. In recent years, the correlation between arsenic exposure, cytotoxicity and genotoxicity, mutagenicity, and tumor promotion has been established, as well as the association of arsenic exposure with perturbation of physiologic processes, generation of reactive oxygen species, DNA damage, and apoptosis induction. Trivalent forms of arsenic have been found to induce apoptosis in several cellular systems with involvement of membrane-bound cell death receptors, activation of caspases, release of calcium stores, and changes of the intracellular glutathione level. It is well known that calcium ion deregulation plays a critical role in apoptotic cell death. A calcium increase in the nuclei might lead to toxic effects in the cell. In this review, we highlight the relationship between induced disturbances of calcium homeostasis, genomic damage, and apoptotic cell death caused by arsenic and its organic derivatives
Note on New KLT relations
In this short note, we present two results about KLT relations discussed in
recent several papers. Our first result is the re-derivation of Mason-Skinner
MHV amplitude by applying the S_{n-3} permutation symmetric KLT relations
directly to MHV amplitude. Our second result is the equivalence proof of the
newly discovered S_{n-2} permutation symmetric KLT relations and the well-known
S_{n-3} permutation symmetric KLT relations. Although both formulas have been
shown to be correct by BCFW recursion relations, our result is the first direct
check using the regularized definition of the new formula.Comment: 15 Pages; v2: minor correction
The Momentum Kernel of Gauge and Gravity Theories
We derive an explicit formula for factorizing an -point closed string
amplitude into open string amplitudes. Our results are phrased in terms of a
momentum kernel which in the limit of infinite string tension reduces to the
corresponding field theory kernel. The same momentum kernel encodes the
monodromy relations which lead to the minimal basis of color-ordered amplitudes
in Yang-Mills theory. There are interesting consequences of the momentum kernel
pertaining to soft limits of amplitudes. We also comment on surprising links
between gravity and certain combinations of kinematic and color factors in
gauge theory.Comment: 19 pages, 1 figur
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